Color Space Analysis of Mutual Illumination
Funt, B.V., and Drew, M., "Illumination Estimation Using a Multilinear Constraint on Dichromatic Planes,"
IEEE Transactions on Pattern Analysis and Machine Intelligence, 15(12) 1319-1325, 1993.
Abstract:
Mutual illumination occurs when light reflected from one
surface impinges on a second one. The resulting additional illumination
incident on the second surface affects both the color and intensity of
the light reflected from it. As a consequence, the image of a surface
in the presence of mutual illumination differs from what it otherwise
would have been in the absence of mutual illumination. Unaccounted for
mutual illumination can easily confuse methods that rely on intensity
or color such as shape-from-shading or color-based object recognition. In
this correspondence, we introduce an algorithm that removes mutual illumination
effects from images. The domain is that of previously-segmented
images of convex surfaces of uniform color and diffuse reflectance where
for each surface the interreflection occurs mainly from one other surface
and can he accurately accounted for within a one-bounce model. The
algorithm is based on a singular value decomposition of the colors
coming from each surface. Geometrical information about where on
the surface the colors emanate from is not required. The RGB triples
from a single convex surface experiencing interreflection fall in a plane;
intersecting the planes generated from two interreflecting surfaces results
in a unique interreflection color. Each pixel can then he factored into
its interreflection and no-interreflection components so that a complete
no-interreflection image is produced.
Full text (pdf)
Keywords:
Mutual illumination, interreflection, color vision, color
histogram, computer vision, shape from shading
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